This disclosure relates to a developer housing, and more particularly, to a seal for a magnetic developer housing.
In the process of electrophotographic printing, a photoconductive member is uniformly charged and exposed to a light image of an original document. Exposure of the photoconductive member records an electrostatic latent image corresponding to the informational areas contained within the original document. After the electrostatic latent image is recorded on the photoconductive surface, the latent image is developed by bringing a developer material into contact therewith. Generally, the developer material comprises toner particles adhering triboelectrically to carrier granules. The toner particles attracted from the carrier granules to form a toner powder image on the photoconductive member that corresponds to the informational areas contained within the original document. This toner powder image is subsequently transferred to a copy sheet and permanently affixed thereto in image configuration.
In electrophotographic printing machines, magnetic rolls are frequently employed in the developing station and the cleaning station. Typically, the magnetic roll includes a stationary magnet having a rotating tube positioned concentrically thereabout. At the developer station, a developer material of magnetic carrier granules having toner particles adhering triboelectrically thereto is attracted to the tube by the magnetic field generated by the magnetic roll. The tube surface is usually roughened so that the frictional force between the developer material and the tube causes the developer material to rotate with the tube. The developer material is advanced by the tube to a position closely adjacent the electrostatic latent image recorded on the photoconductive member. At the cleaning station, a layer of carrier granules adheres to the tube and moves therewith. As the layer of carrier granules pass closely adjacent to the photoconductive member, residual toner particles are attracted to the layer of carrier granules and move therewith away from the photoconductive member. In this way, residual toner particles are cleaned from the photoconductive member. A copier employing a magnetic roll is shown in U.S. Pat. No. 4,823,102 issued Apr. 18, 1989 to Abraham Cherian et al.
It is critical for performance of the printer that the developer housing in which the magnetic roll is supported is sealed with respect to the magnetic roll in order to prevent toner from escaping into the insides of the printer. This has been accomplished in the past, but with excessive cost. For example, rare earth magnetic seals have been used successfully, but they are too expensive. Felt seals have been used to seal the magnetic roll to the developer housing, however, they present installation, adhesive shelf life, component contamination from adhesives, ineffective adhesives and ineffective adhesive problems which allow the magnetic roll to spin in the seal out of position with respect to the photoconductive member.
Obviously, there is still a need, in magnetic developer housings for an inexpensive magnetic roll seal.
Accordingly, a device for sealing a magnetic roll to a developer housing is disclosed that answers the above-mentioned problem by including a plastic retainer having side walls that are spring loaded with a felt seal positioned within the said walls. The spring loaded side walls of the plastic retainer hold the felt seals in place to facilitate installation onto the magnetic rolls.
While this disclosure will be described hereinafter in connection with a preferred embodiment thereof, it will be understood that it is not intended to limit the invention to that embodiment. On the contrary, it is intended to cover all alternatives, modifications and equivalents as may be included within the spirit and scope of the invention as defined by the appended claims.